Dashpot control for vehicle engine throttle valves



Oct. 26, 1954 T. M. BALL 2,692,551

DASHPOT CONTROL FOR VEHICLE ENGINE THROTTLE VALVES Filed March 14, 1951 2 Sheets-Sheet 1 INVENTOR- Tiamas M3477 BY EAL #W Oct. 26, 1954 T. M. BALL 2,692,651

DASHPOT CONTROL FOR VEHICLE ENGINE THROTTLE VALVES v #9 if! g/ //5 j/ 17/ WK 2 2/2 I N VEN TOR. TZamas /7 BY I HM A H Patented Oct. 26, 1954 DASHPOT CONTROL FOR VEHICLE ENGINE THROTTLE VALVES Thomas M. Ball, Detroit, Mich., assignor to Chrysler Gorporation, Highland Park, Mich, a

corporation of Delaware Application March 14, 1951, Serial No. 215,595

11 Claims.

This invention relates to throttle valve control devices to be used especially in conjunction with motor vehicle internal combustion engines and deals particularly with a control for throttle valve closing movement.

It is Well known at this time that an internal combustion engine has a tendency to stall when, at relatively low vehicle speeds, the driver suddenly releases the usual accelerator pedal to allow the throttle valve to suddenly close. This engine stalling tendency is known to be especially pronounced in motor vehicles equipped with a fluid coupling through which the drive is transmitted.

Heretoiore, it has been customary to provide some form of dashpot for retarding the last part of throttle valve closing movement so that when the accelerator pedal is suddenly released, the throttle valve has its final closing movement retarded so that the fuel supply system and other factors which are disturbed and which give rise to engine stalling have an opportunity to become balanced or adjusted to the coast drive conditions whereupon the throttle valve may thereafter close without danger of engine stall.

The foregoing throttle retarding devices have the disadvantage that they also operate at relatively high vehicle speeds thereby preventing full use of the engine as a coast brake due to the fact that when the accelerator pedal is released, the throttle valve does not fully close until after an appreciable time during which the aforementioned dashpot acts. Furthermore, where the vehicle is equipped with a change speed mechanism that functions as a result of allowing the engine to coast down in its speed, the foregoing dashpot device has the disadvantage of increasing the time required to effect changes in the speed ratio drive due to the dashpot delaying the engine speed retardation.

In my copending patent application Serial No. 643,819 filed January 26, 1946, now U. 5. Patent 2,592,375, and in my previously issued U. S. Patents Nos. 2,314,570 and 2,334,857, I have provided dashpot controls for engine throttle valve closing movement that overcome the aforementioned difficulties. In each of the above-noted patents the dashpot controls incorporate means for rendering the dashpot ineffective for throttle closing retardation at times such as high vehicle speeds when the engine does not tend to stall as an incident to sudden release of the accelerator pedal. The above-noted dashpot controls have the dashpot mechanisms associated with either the liquid fuel in the carburetor body or with the manifold vacuum of the fuel intake manifold and as a consequence certain troublesome problems associated with these engine charging media enter into the operation of the dashpot controls. Furthermore, due to the type of operating media used in the dashpots of the above noted dashpot constructions, it is practically imperative that the dashpot devices be formed integrally with or be directly mounted on the associated carburetor device. It is thought to be obvious that it may be more convenient and more economical to mount the throttle valve control dashpot at a location remote from the carburetor provided the same degree of throttle control can be secured.

It is a primary object of this invention to provide an improved and simplified form of dashpot control for throttle valve closing movement that is disassociated from the fuel media, liquid or gaseous, that passes from the carburetor into the vehicle engine.

It is a further object of this invention to provide an air dashpot to control throttle valve closing movement which dashpot may be located at any point on the vehicle where it may engage an element of the throttle valve control linkage.

It is another object of this invention to provide an air dashpot for control of the engine throttle valve closing movement which dashpot has a vehicle speed responsive by-pass valve associated with the dashpot in such a manner that retardation of throttle valve closing movement is practically inconsequential at certain vehicle speeds while being a major influence at other predetermined vehicle speeds.

It is still another object of this invention to provide an improved, simplified form of dashpot having valve means associated therewith to provide means for varying the cushioning efiect of the dashpot. 1

It is still another object of this invention to provide a simplified, improved form of dashpot having novel valve controlled means to transfer the dashpot operating medium between opposed, diaphragm separated, chambers of the dashpot.

It is still another object of this invention to provide a novel form of throttle valve control device that is particularly adapted for use with automatic or semi-automatic types of transmissions wherein the changes in speed ratio drive are controlled by or eiiected through release of the accelerator pedal.

Other objects and advantages of this invention will become readily apparent from a reading of the attached description and a consideration of the related drawings wherein:

Fig. l is a diagrammatic side elevational view of a motor vehicle internal combustion engine and its associated power transmission elements that include a throttle valve dashpot device in accordance with this invention;

Fig. 2 is an enlarged sectional elevational view of the dashpot device embodying this invention;

Fig. 3 is a side elevation of the dashpot device, the view being taken in the direction indicated by the arrow 3 of Fig. 2;

Fig. 4. is a schematic wiring diagram for the electrically operated controls for the dashpot device shown in Figs. 1-3

Fig. 5 is a sectional elevational view of a semiautomatic type of power transmission unit that is particularly adapted for use with a throttle valve controlled by an air dashpot of the type herein disclosed; and

Fig. 6 is a diagrammatic view, partly in sectional elevation, of the control system for the power transmission unit shown in Fig. 5.

My invention may be used advantageously in connection with any vehicle power transmission system. In my aforesaid copending application and in my patents I have illustrated one type of drive system that is well adapted for use with my present improvements. However, in order to illustrate the principles of my present invention I have merely shown the same in connection with a schematic vehicle drive mechanism in Figs. 1-4, it being understood that this drive mechanism may take a variety of forms although it is espe cially adapted for drive systems of the type shown in Figs. 5 and 6 where, at times, it is desired to allow the engine to rapidly slow down upon release of the accelerator pedal without any retarding of throttle closing movement by the dashpot control while at other times it is desired to retard throttle closing movement to prevent tendency of the engine to stall.

In Fig. 1 the customary internal combustion engine A is arranged, as is now well known, to drive through suitable clutch mechanism B and/or any desired type of transmission change speed mechanism C to the output or propeller shaft 28 which is adapted to drive the usual vehicle driving wheels in accordance with standard practice. The clutch mechanism at B may comprise a slip-drive device such as a fluid coupling, a torque converter, a conventional friction clutch or any combination of these elements.

The engine intake manifold 2! is fitted with an air cleaner 22 and carburetor D having the usual throttle valve 23 mounted in the throat 30 thereof on the rotatable shaft 29. Shaft 29 supports and is adapted to be operated. by the lever 24 and the link 25 that are connected by linkage 26 to the conventional accelerator pedal 21. Accelerator pedal 27 is yieldingly urged by compression spring 28 to a position that tends to close the throttle valve 23.

Mounted on the side of the carburetor D, (see Figs. 2 and 3), by means of the screw attached bracket plate 35, is my novel form of dashpot device E that is adapted to control the closing movement of the throttle valve 23. The dashpot device E comprises a two-piece casing formed of the mating, dished casing parts 36 and 31. Casing parts 36 and 3'! are adapted to be suitably secured together by screws or the like with a flexible diaphragm member 39 mounted therebetween. The diaphragm 39 divides the chamber within the casing into two compartments 4| and 42 respectively.

Casing part 36 has an externally threaded neck portion 43 that extends through a suitable opening a in the support plate 35. The casing neck portion 43 is pierced by an axially extending bore as that loosely receives the plunger rod 45. Plunger rod 35 has its interiorly disposed end 46 connected to the diaphragm 33 in such a manner that movement of the diaphragm 39 is transmitted to the plunger rod 45. The interiorly disposed end portion 55 of plunger rod is pierced by an axially extending bore 41 that is adapted to provide a conduit connection between the chambers ii and 42 of the dashpot device E. Bore 67 in plunger rod 45 is connected to a radially extending cross-bore 18 that connects the plunger rod bore 4'! to the bore 44 in the casing neck portion 43. Loosely mounted in the plunger rod cross bore 48 is a pin or plug element 49. Pin 49 converts the cross bore 48 into a restrictive opening that meters or controls the transfer of air from the chamber 4! to the chamber 42 through the bore or passageway 47. It is obvious that one or more vol? small cross-bores (not shown) could be connected to the rod bore 4? instead of the large pin blocked across bore 48. The pin blocked con struction has the advantage that it is easy to drill without danger of breaking the drill bits and furthermore different sized pins or plugs may be mounted in the large cross bore 48 to vary the metering action on the air or the fluid medium passing through the pliuiger rod bore 41.

Threaded on the neck portion lia of the casing part 3%; is a sleeve nut 51. Sleeve nut 5! provides a convenient means for detachably connecting the casing of the dashpot device E to the support bracket plate 35. Sleeve nut 51 is provided with a reduced diameter outer end portion 52 that has a bore 53 therethrough adapted to loosely support and. guide the outer end portion of the plunger rod 35. The bore 53 in the sleeve nut neck portion 52 is directly connected to the bore M in the casing part neck portion 43 and these aligned, connected bores are sufficiently larger than the outside diameter of the plunger rod 45 so that a clearance space or passage is provided therebetween for the ready transfer of air between the atmosphere and the interior of the casing chamber d2. Thus as the diaphragm 39 is flexed axially air may pass to and from the casing chamber 42 through the clearance spaces 53, A l between the rod 45 and its supporting casing bores. Diaphragm 39 is continuously urged towards the left by the compression spring 55 that is mounted in the casing chamber 4i so as to extend between the casing and one of the dia phragm mounted washers lfi.

Casing part 31 is formed with a bore or passageway Gi that connects the chamber M to a valve receiving bore 62. One end of the valve receiving bore 62 is closed off by a plug element 63 while the other end of the bore 62 receives the ball valve 54 and its operatin mechanism that will subse* quently be described in detail. Valve receiving bore 62 is of stepped construction to provide the valve seat 65. The reduced portion 66 of the valve receiving bore 82 slidably receives the push rod or actuator 6? for the valve 64. The lower end of the push rod 6? has the armature member 68 fixed thereto. Armature 68 is preferably of some ferrous material, or a similar material, so that it is responsive to magnetic attraction. Push rod 67. and its attached armature member 68 are normally urged upwardly by the compression spring 69 which action tends to hold the valve 54 off its seat 65. The spring 69 is seated in a recess H in the core element [2 of the electromagnetic solenoid unit 13.

The solenoid unit 13 has its coil element 14 surrounding and fixed to the core element 12 in more or less conventional manner. Electrical energy for the energization of the coil 14 is supplied thereto through the contact elements 15. Energization of the coil 74 will magnetize the core 72 such that armature element 53 will be attracted downwardly towards the core 12 and thereupon push rod 57 will be retracted sufficiently to permit the ball valve 64 to sink into engagement with its seat 65 and seal off the conduit connection between the valve receiving bore portions 62, B6.

The energization of the solenoid coil 14 is adapted to be automatically controlled by a vehicle speed responsive governor element 80. In the form herein disclosed the governor element 80 is of the flyball type and is drivingly connected by pinion gearing 8| (see Fig. 4) to a worm gear 82 carried by the vehicle drive train propeller shaft 2-5. It is thought to be obvious that other forms of vehicle speed responsive devices may be substituted for the governor 80 herein disclosed. Governor 8|) is arranged to operate a switch contact 85. At low vehicle speeds and when the vehicle is at rest the governor 8| permits the spring 31 to cause engagement of the switch contact 55 with the switch contact 86. From Fig. 4 it is thought to be obvious that the solenoid coil i l will be energized by the closing of contacts 85, 86 and the valve 64 will thereupon be closed. When the vehicle speed is increased to a predetermined speed the governor 80 will open contacts 85, 86 and at all vehicle speeds above this predetermined speed the contacts 85, 86 will remain open, the solenoid coil 14 will be deenergized and the valve 64 will be kept open by the spring H.

The electrical circuit for control of the solenoid i3 is shown in Fig. 4 and comprises a source of electrical energy 89, such as a battery, that is grounded at 90 and connected by a conductor 8| through an ammeter 92 and an ignition switch 93 to one of the contacts of the solenoid coil 14. Another contact 16 of coil 14 is connected by conductor 94 to the switch contact 86 that is engageable with the governor operated switch contact 35. Switch contact 85 is grounded at 95.

The casing of the dashpot device E includes in addition to the passage or bore 6| another bore or passageway 38. Bore 98 connects the casing chamber 42 to the reduced portion 66 of valve bore 52 that is located on the downstream side of the ball valve 64. With the arrangement disclosed it will be seen that when valve 64 is unseated or open then movement of the plunger rod 45 and the connected diaphragm 39 towards the right will force air out of chamber 4| through two different escape channels. The major portion of the air in chamber 4| may freely flow from chamber 4| through passage 6| into bore 62, through open valve 64 into bore 66 and thence through passage 98 into chamber 42 from whence it may escape to the atmosphere through the clearance spaces 44, 53 extending between the plunger rod 45 and the neck 43. 5| of the casing. At the same time that the air, or other medium contained in chamber 4|, is passing between chambers 4i and 42 by the aforementioned escape route, a small percentage of the air in chamher 4! may escape from chamber 4| by a second route due to it being forced through plunger rod bore 4i and out through the cross-bore 48 to the aforesaid clearance passages 44, 53. It is apparent that only a small percentage of the air in -It is thought to be rather obvious that when valve 64 is open that then dashpot .E will offer very little resistance to movement of the rod 45 towards either the .right or the left. However when valve 54 is seated and passage 6| is blocked ofi from passage 98 then on movement of the plunger rod towards the right the air escaping from chamber 4| must all pass through the second mentioned escape route, that is, through the bore 41 and the restricted opening in the crossbore 48. Thus when valve 64 is closed there is only a single air escape passage for the air that is trapped in chamber 4| and as this escape passage comprises the restricted opening in crossbore 48, it is thought to be obvious that during the times when the valve 64 is seated the dashpot device E provides a very definite retarding action on the movement of the plunger rod 45 towards the right. On the tendency for movement of the diaphragm 39 towards the left, when valve 54 is closed, it will be noted that there is no resisting or retarding effect offered by the closed valve 64 for the air or other medium in chamber 42 is forced out of chamber 42 back through by-pass 98 into bore portion 66 and upagainst the seated valve 64 such that valve 64 will be moved ofi its seat and the air in chamber 42 transferred back into the chamber 4|. Thus it will be seen that the bypass channel 98 has a material influence on the operation of the diaphragm whether the diaphragm is moved axially to the right or to the left.

The full lines in Fig. 1, as well as Fig. 2, indicate one of the preferred locations for the dashpot device E in a conventional motor vehicle chassis arrangement. Other possible locations for the dashpot device E in a motor vehicle chassis or body are indicated by the numerals 99 and H30 and are shown in broken lines in Fig. 1. It is thought to be obvious that the dashpot device E can be located at any point in a motor vehicle chassis or body provided it is arranged to have the dashpot plunger rod 45 engageable with some portion of the throttle valve control linkage or an extension thereof. In Figs. 1 and 2 the dashpot device E is shown mounted on the carburetor body by the bracket plate 35. The outer end of the dashpot plunger rod 45 is arranged so as to directly engage the throttle valve lever arm 24 that is fixed to the throttle valve support shaft 29. The outer end of rod 45 may be rounded as shown to reduce sliding friction between the rod 45 and the lever 24 during relative movement therebetween. Figs. 1 and 2 show the throttle valve and the associated dashpot mechanism in the closed throttle position of the throttle valve. This particular arrangement of the dashpot device E has the advantage of causing the dashpot plunger rod 45 to act directly on the throttle valve 23 and this eliminates the possibility of any slack or looseness in the throttle valve control linkage modifying or altering the intended action of the dashpot device. With properly designed throttle valve control linkages that are free of slack, it is obvious that any of the other locations 99 or I00 for the dashpot E would be equally as acceptable and this would have the further advantage that they removethe dashpot E from the vicinity of the carburetor which de- 7 vice is already surrounded by numerous engine control mechanisms.

With the arrangement shown in Figs. 1 and 2, it is apparent that on depression-of the accelerator pedal 27 the throttle valve 23 and connected lever arm 24 will be rotated in a counterclockwise direction to accomplish opening of the throttle valve. During opening movement the lever arm 26 may move freely as the dashpot E has no effect whatever on throttle valve opening movement. The spring 55 of the dashpot E will cause the diaphragm 39 and connected push rod 45 to move towards the left and follow up the movement of the lever arm 24 during at least a portion of the throttle valve opening movement. As before mentioned the dashpot device E offers no retarding effect to leftward shift of the diaphragm 39 due to the fact that the air in chamber 42 may freely flow into the expanding chamber 1H regardless of the condition of valve 64. When the accelerator pedal 21 is released after throttle valve opening movement the lever arm 24 and valve 23 are urged clockwise to closed throttle position by the spring 28 and possibly by other resilient means not shown. The vehicle speed responsive governor 80 then automatically determines whether the dashpot E is to be effective to retard closing movement of the throttle valve. If the vehicle speed is above say 20 miles per hour then the contacts 85, 85 remain open and solenoid 73 is not energized so that valve E l is open and the diaphragm 39 is easily shifted to the right due to the air in chamber lI freely passing into chamber 32 and escaping to the atmosphere as previously described. Under such conditions engine braking is obtainable due to the rapid closing of the throttle valve. If on the other hand the vehicle speed should be below 20 miles per hour when the accelerator pedal 2'! is released, then the governor 80 would have closed contacts 85, I36 and the solenoid I3 would be energized and valve 62 would be closed. Under these circumstances the movement of the plunger rod 45 towards the right by its engagement with the lever 24 on throttle valve closing movement causes the air in chamber ll to escape by passing through the restricted opening in plunger rod cross bore 38. Thus a very definite retarding effect is applied to the closing movement of the throttle valve 23 when governor 89 has closed valve 64. The critical speed of 20 miles per hour for control of the solenoid T3 is purely a matter of choice and any other speed could be used that would accomplish the desired effect.

The invention hereinabove described is thought to provide an improved form of control for throttle valve closing movement that is simple, compact, free of any association with the fuel charge to the engine, not dependent on relative temperatures or pressure, and a device that can be easily and economically installed at any number of locations on the vehicle body or chassis.

In Figs. 5 and 6 I have shown a power transmission unit T in which the changes in speed ratio occur in response to release of the accelerator pedal. This type of power transmission is especially well suited for utilization of this invention due to the fact that this invention will insure fast speed ratio changes while preventing engine stall.

The transmission T comprises an input shaft IZE) adapted to be driven by the engine crankshaft (not shown), an output shaft I2I, a countershaft I22, and a countershaft gear cluster I I 9 rotatably mounted. on the counter-shaft I22. Input pinion I23 carries clutch teeth I24 and a friction cone I25 that is constantly engaged by the blocker ring I It. The blocker II 5 carries blocker teeth I26 adapted to be engaged by the blocker teeth I2l' of clutch sleeve S when the latter sleeve S is biased forwardly under synchronous conditions in the rotation of pinion I23 and sleeve S. This sleeve S together with the clutch teeth I24 comprise relatively movable drive control elements for effecting step-up and step-down manipulation of the transmission.

Blocker I I6 is lightly urged against the cone I25 by a spring I if and has a lost-motion connection at I09 with the slotted end of a hub I08 of a high speed gear I23 such that the blocker II 6 may move relative to sleeve S between two positions blocking the sleeve, such positions being known as the drive block and the coast block positions of the blocker ring I I6 depending on whether pinion I23 appreciably leads or lags the speed of the sleeve S. The sleeve S is splined on hub i 58 at Iil'l, the arrangement being such that whenever sleeve S is rotating faster or slower than pinion I23 then the blocker teeth I26 will be aligned with the ends of the teeth of sleeve S and thus prevent shift of the sleeve S into contact with the pinion teeth E24. However, when the pinion I 23 is rotating faster than sleeve S and gear I 28 and the sleeve S is biased forwardly into blocked position, a reduction of engine speed will cause input shaft l as and pinion I23 to slow down and as the pinion 12S and sleeve S pass through a synchronous relationship the blocker H6 is moved from its drive blocking position toward its coast blocking position and when substantially mid-way therebetween will unblock the sleeve S and. allow the sleeve teeth I2? to pass between the blocker teeth E26 and clutch with pinion teeth I24.

Gear I28 is rotatably mounted on output shaft i225 but is keyed to the clutch sleeve S and is in constant engagement with countershaft cluster gear 52g. Accordingly, countershaft cluster II9 may be power driven from gear I28 if sleeve S is engaged with pinion teeth I24. If sleeve S is urged to the right in Fig. 5 by the mechanism shown in Fig. 6 and disengaged'from pinion teeth I22, the power drive of the countershaft cluster i I9 occurs through pinion I23, gear I I8 and overrunning clutch F.

A manually operated clutch G is adapted to either lock gear I28 to the driven shaft I2I or to lock gear I36 to the driven shaft I21. Gear I 30 is in constant engagement with countershaft cluster gear Hit. A reverse gear I32 is keyed to the output shaft E2I and is adapted to be selectively engaged with a shiftable idler gear (not shown) that is driven by the countershaft gear ISI.

The manually operated clutch G has a splined connection with a hub I07 fixed to shaft I2I. There is associated with clutch G any commercial type of blocker synchronizers IDS such that clutch G may be shifted either forwardly to high range or rearwardly to low range to synchronously clutch shaft i2I either with the high speed gear I28 at the teeth I or with the low speed gear 30 at the teeth IM. Manual shifts of clutch G are facilitated by release of a main clutch (not shown) that is operated by the usual clutch pedal.

There are four forward speeds which may be obtained from this transmission. The first two speeds occur when clutch G is shifted to the right in Fig. 5;

(a) A first speed when sleeve S is disengaged from teeth I24 and manual clutch G is locking 9. gear I38 to output shaft I2 I. The drive then occurs through pinion I23, gear H3, overrunning clutch F, countershaft cluster IIEI, gear I3I, gear I38, and output shaft I2I.

(b) A second speed when sleeve S is in engagement with teeth I24 and manual clutch G is looking gear I38 to output shaft I2I. The drive then occurs through teeth I24, sleeve S, gear I28, gear I29, countershaft cluster H9, gear I3I, gear I38, and output shaft I2 I.

If manual clutch G is shifted to the left in Fig. 5:

(c) A third speed when sleeve 8 is disengaged from teeth I24 and manual clutch G is looking gear I28 to output shaft I'ZI. The drive then occurs through pinion I23, gear II8, overrunning clutch F, countershaft cluster H9, gear I23, gear I28, and output shaft I2I.

(d) A fourth speed when sleeve S is in engagement with pinion teeth I24 and manual clutch G is looking gear I28 to output shaft I2 I. The drive then occurs through teeth I24, sleeve S, gear I28, and through clutch G to output shaft I2I.

It should be noted that the engagement of sleeve S with pinion teeth I24 through the blocker device H6 is dependent upon synchronizing the speeds of rotation of gear I24 and sleeve S. Throttle control is directly related to the length of time required for this synchronization.

Fig. 6 illustrates automatic means for urging sleeve S into or out of engagement with pinion teeth I24 as discussed above and thereby accomplishing an automatic selection between the first and second or third and fourth speeds (depending upon the position of manual clutch G) as listed above. Fluid servomotor M controls shift of sleeve S. This motor comprises a cylinder I40 slidably receiving a piston I39 which slidably receives a rod I36 which is mounted to reciprocate in guideways I33 and I34. Fixed to this rod is the collar I3'I of a yoke I38 connected with sleeve S to effect shift thereof. A relatively small force pre-loaded engaging spring I35 is disposed between piston I39 and yoke I38 to provide a lost motion thrust transmitting connection such that piston I39 may move forwardly or to the left for its power stroke being limited by abutment [03 in advance of the full clutching shift of sleeve S. The shift towards the left of the sleeve S is limited by engagement of the yoke collar I31 with the rear or exposed end of guideway I33. A relatively large force pre-loaded kickdown spring MI is disposed between abutment I03 and piston I39 and serves to return the piston I39 and sleeve S to the downshifted Fig. 5 position. The spring MI is thus adapted to effect disengaging bias of sleeve S relative to teeth I24.

R/od I33 has a shoulder I02 which in Fig. 5 engages the face of piston I39 but which, when the piston and rod I36 are moved to the end of their forward or upshifted strokes, is spaced rearwardly of the piston to provide a gap equal to the difference in the strokes of the piston I39 and rod I38. This gap is utilized to close an ignition control switch H for interrupting the engine ignition system. Piston I39 is provided with an annular groove I42 formed in its skirt to define a cam surface which operates switch H. Switch H interrupts the engine ignition to unload or relieve driving torque long enough to permit a disengagement of sleeve S from the pinion teeth I24.

A pressure fluid supply system is connected with the servomotor M by a passage I43 which is connected to valve J. Pump I44 through tubing I45 draws oil from source I46. Pump I44 may be driven from some moving vehicle part, preferably a car speed responsive part such as a gear 253 on countershaft cluster IIS. Pressure relief valve I41 permits the return of oil to the source I46 when the passage I43 is blocked off from conduit I45 by valve J. When valve J is raised above its Fig. 6 position by compressed spring I49 on de-energization of solenoid I48, passage I43 is connected to the oil pressure supply conduit I45 and piston I39 is moved towards the left to cause upshift of sleeve S. Solenoid I48, when energized, lowers valve J to its Fig. 6 position against the force of spring I49 which normally raises the valve J so that pressurized oil in line I45 is connected to line I43 and can cause motor M to shift sleeve S to the left.

Two parallel switches control the energizing of solenoid I48 which is electrically connected to the usual grounded storage battery 218' as illustrated in Fig. 6. Switch 258 is opened by a governor 25I driven at 253 (Fig. 5) when sufficient vehicle speed is obtained. Switch 252 is manually closed by depressing the accelerator pedal 21. The last portion of travel in depressing accelerator pedal 21 closes switch 252. Electrical circuit means for this purpose includes the grounded storage battery 2H) for supply of electrical energy through ammeter 2| I, ignition switch 2I2, to a wire 2I3,

thence through solenoid I48 to a terminal 2I4 from which either of two parallel grounds '2I5 or 2I6 will complete a circuit to energize solenoid I48 through wires 2 H or 2I8a respectively.

The relation of the. governor 25I to the system may be explained by an example. When manual clutch G of Fig. 5 is looking gear I28 to shaft I2I for normal driving in third or fourth forward speeds and the engine is idling with switch 258 closed and switch 252 open, solenoid I48 is energized and valve J closed. Therefore, sleeve S is not engaged with transmission pinion gear teeth I24 and operation will be in the third speed gear explained above driving directly from pinion I23 through countershaft cluster I13 and gear I28. The slip drive coupling that is connected between the engine and the transmission will permit the vehicle to remain stationary while the engine is idling. When the carburetor throttle valve is opened slightly the vehicle will be driven forward. When suflicient vehicle speed is obtained switch 258 is opened by governor 25'! and solenoid I48 is deenergized. Spring I49 will open valve J and oil under pressure will be permitted to enter passage I43 and move piston I353 to the left thereby urging sleeve S to the left in Fig. 5 although it is restrained by blocker H8. When synchronous speeds of sleeve S and the pinion 23 are obtained by a release of the accelerator pedal 21 then the teeth of sleeve S pass through the blocker teeth I26 and engage the pinion teeth I24. The vehicle is then geared for drive in fourth speed or direct drive.

Governor 25I also initiates an automatic trans mission downshift when vehicle speed is reduced sufficiently to cause the governor to close switch 250. This energizes solenoid I48, closes valve J, vents servomotor M and permits spring I 4! to move piston I39 to the right momentaril interrupting engine ignition and through spring MI and yoke I38 disengaging sleeve S frompinion gear teeth I24 and causin the drive to be downshifted to the third speed previously described.

The function of switch 252 is to provide means for the driver to selectively cause a downshift 11 from fourth speed to third speed, or if manual clutch G is in the low speed range position, from second speed to first speed. If when the vehicle is travelling in the direct drive fourth speed with switches 250 and 252 open, and for example a steep hill is encountered, the driver may push accelerator pedal 27 to its extreme down or throttl opening position and the aforementioned downshift to third speed will be achieved. Tooth 251 on arm 256 will close switch 252, ground the solenoid circuit at 216, thereby energizing solenoid I48 and by means of the venting of oil pressure from servomotor M and the action of spring ldl will move piston I39 towards the right interrupting engine ignition by switch H. Movement of piston I39 to the right will move yoke i38 and sleeve S to the right thereby creating the conditions necessary for the downshift to third speed. An automatic upshift back to fourth speed or direct drive will occur after release of accelerator pedal when the conditions are such as to dictate the upshift.

By the incorporation of the air dashpot device E of Figs. 1-4 in the transmission control system shown in Fig. 6, it is thought to be obvious that when the vehicle is travelling above the selected governor speed, say 15 to miles per hour or thereabouts, that then the devic E is inoperative to retard throttle valve closing movement and the release of th accelerator pedal 27 will permit the engine speed to drop down quickly to effect a quick synchronization of the speeds of pinion I23 and sleeve S. Accordingly, a fast change, either downshift or upshift, in speed ratio drive may be accomplished even with the dashpot controlling the carburetor of a vehicle having a transmission similar to that shown in Fig. 5. However, when the vehicle speed is below the selected governor speed the dashpot device E will be operative to retard throttle valve closing movement and thus prevent engine stall. When the vehicle speed is below 15 M. P. H. then usually there will be no need or desire to release the accelerator 2'! to accomplish the automatic speed ratio upshift. In initiating drive through the Fig. 5 transmission, the vehicle would normall be accelerated up beyond or miles per hour before the accelerator 2! would be released to accomplish the automatic upshift. Thus the dashpot devic E is rendered inoperative to retard throttle closing movement before the accelerator controlled speed ratio change calls for a quick release of the throttle valve to accomplish the upshift.

Iclaim:

l. A dashpot device for modifying the normal movement of a control valve or the like comprising a casing having a pair of chambers separated by a flexible, anchored, diaphragm, a plunger element carried by said diaphragm having a portion adapted to be engaged with said control valve, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, an air inlet to one of said chambers, a first passageway connecting said chambers, and a second passageway connecting said chambers, said first passageway including means arranged such that the passage of the air medium between said chambers through said first passageway is materially retarded as compared to the passage of the air medium between said chambers through said second passageway.

2. A dashpot device for modifying the normal movement of a control valve or the like comprising a casing having a pair of chambers separated by a flexible, anchored, diaphragm, a plunger element carried by said diaphragm having a po'r-' tion adapted to be engaged with said control valve, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, an air inlet to one of said chambers, a first passageway connecting said chambers, a second passageway connecting said chambers, said first passagewa including means arranged such that the passage of the air medium between said chambers through said first passageway is materially retarded as compared to the passage of the air medium between said chamhers through said second passageway, and valve means associated with said second passageway to control the interchange of the air medium between said chambers through said second passageway.

3. A dashpot device for modifying the normal movement of a control valve or the like comprising a casing having a pair of chambers separated by a flexible, anchored, diaphragm, a plunger element carried by said diaphragm having a portion adapted to be engaged with said control valve, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, an air inlet to one of said chambers, a first passageway comiecting said chambers, a second passageway connecting said chambers, said first passageway including mean ar ranged such that the passage of the air medium between said chambers through said first passageway is materially retarded as compared to the passage of the air medium between said chambers through said second passageway, valve means associated with said second passageway to control the interchange of the air medium between said chambers through said second passageway, and means to automatically operate said valve means.

4. A dashpot device for modifying the normal movement of a control valve or the like comprising a casing having a pair of chambers separated by a flexible, anchored, diaphragm, a plunger element carried by said diaphragm having a portion adapted to be engaged with said control valve, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, a gas inlet to one of said chambers, a first passageway connecting said chambers, and a second passageway connecting said chambers, said first passageway includin a restrictive opening arranged such that the passage of the gas medium between said chambers through said first passageway is materially retarded as compared to the passage of the gas medium between said chambers through said second passageway.

5. A dashpot device for modifying the normal movement of a control valve or the like comprising a casing having a pair of chambers separated by a flexible, anchored, diaphragm, a plunger element carried by said diaphragm having a portion adapted to be engaged with said control valve, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, a gas inlet to one of said chambers, a first passageway connecting said chambers, a second passageway connecting said chambers, said first passageway including a portion with a plug element arranged therein with clearance space extending thereabouts arranged such that the passage of the gas medium between said chambers through said first passageway is materially retarded as compared to the passage of the gas medium between said chambers through said second passageway, and valve means asso- 13' ciated with said second passageway to control the interchange of the gas medium between said chambers through said second passageway.

6. An air dashpot for controlling closing movement of a carburetor throttle Valve comprising a casing having a pair of adjacent chambers separated by a flexible, anchored, diaphragm element, a plunger rod extending through the casing and one of the chambers having portions connected to said diaphragm for movement thereby and another portion engageable with the throttle valve, an air inlet to said one chamber, a first air passageway extending through said diaphragm having restriction means associated therewith to meter the interchange of air between said chambers through said first passageway, a second air passageway extending between said chambers, a valve mounted in said second passageway adapted to be closed to seal off communication between said chambers through said second passageway, resilient means normally opening said valve to provide a pair of passage ways to transfer air between said chambers on movement of said plunger rod, and electrically operated means to effect closing of said valve to cause the interchange of air between said chambers to be through said first passageway whereby the restriction means therein produces a dashpot action that retards shift of the plunger rod in one direction.

'7. An air dashpot for controlling closing movement of a carburetor throttle valve comprising a casing having a pair of adjacent chambers separated by a flexible, anchored, diaphragm element, a plunger rod extending through the casing and one of the chambers having portions connected to said diaphragm for movement thereby and another portion engageable with the throttle valve, an air inlet to said one chamber, a first air passageway extending through said diaphragm having restriction means associated therewith to meter the interchange of air between said chambers through said first passageway, a second air passageway extending between said chambers, a valve mounted in said second passageway adapted to be closed to seal off communication between said chambers through said second passageway, resilient means normally opening said valve to provide a pair of passageways to transfer air between said chambers on movement of said plunger rod, a solenoid energizable to effect closing of said valve and electrical circuit means for said solenoid to automatically control energization of said solenoid.

8. An air dashpot for controlling closing movement of a motor vehicle engine curburetor throttle valve comprising a casing having a pair of adjacent chambers separated by a flexible, anchored, diaphragm element, a plunger rod extending through the casing and one of the chambers having portions connected to said diaphragm for movement thereby and another portion engageable with the throttle valve, an air inlet to said one chamber, a first air passageway extending through said diaphragm having restriction means associated therewith to meter the interchange of air between said chambers through said first passageway, a second air passageway extending between said chambers, a valve mounted in said second passageway adapted to be closed to seal oif communication between said chambers through said second passageway, resilient means normally opening said .valve to provide a pair of passageways to transfer air between said chambers on movement of said 14 plunger rod, a solenoid energizable to effect clos ing of the valve, and an electrical circuit means connected to said solenoid including a vehicle speed responsive switch to automatically control energization of the solenoid.

9. An air dashpot device adapted to have a portion thereof engaged with the throttle valve control of an internal combustion engine carburetor to provide for selective retardation of the closing movement of the throttle valve comprising a casing having a pair of adjacent air chambers separated by a flexible, anchored, diaphragm, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, a plunger rod piercing said casing, the said one chamber and said diaphragm and fixedly connected to said diaphragm for movement therewith, said plunger rod having a portion engageable with the throttle valve, a bore in said plunger rod providing a first passageway interconnecting said chambers, restriction means associated with said bore to meter the air passing through said bore, an air inlet to said one chamber, a second passageway connecting said chambers including a stepped bore providing a valve seat, a ball valve engageable with said seat, a push rod slidably mounted in said stepped bore and engageable with said ball valve to effect unseating thereof, resilient means normally urging said push rod into engagement with said ball valve, solenoid means energizable to disengage said push rod from said ball valve to seat said valve, and electrical circuit means for said solenoid to automatically control energization thereof.

10. In a motor vehicle, an air dashpot device adapted to have a portion thereof engaged with the throttle valve control of the motor vehicle internal combustion engine carburetor to provide for selective retardation of the closing movement of the throttle valve comprising a casing having a pair of adjacent air chambers separated by a flexible, anchored, diaphragm, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, a plunger rod piercing said casing, the said one chamber and said diaphragm and fixedly connected to said diaphragm for movement therewith, said plunger rod having a portion engageable with the throttle valve, a bore in said plunger rod providing a first passageway interconnecting said chambers, restriction means associated with said bore to meter the air passing through said bore, an air inlet to said one chamber, a second passageway connecting said chambers including a stepped bore providing a valve seat, a ball valve engageable with said seat, a push rod slidably mounted in said stepped bore and engageable with said ball valve to effect unseating thereof, resilient means normally urging said push rod into engagement with said ball valve, solenoid means energizable to disengage said push rod from said ball valve to seat said valve, and electrical circuit means for said solenoid to automatically control energization thereof comprising a vehicle speed responsive switch to energize said solenoid below a predetermined vehicle speed so as to thereupon close off said second passageway and activate the dashpot to retard throttle valve closing movement.

11. In a motor vehicle, an air dashpot device adapted to have a portion thereof engaged with the throttle valve control of the motor vehicle internal combustion engine carburetor to provide for selective retardation of the closing movement I 5 of the throttle valve comprising a casing having a pair of adjacent air chambers separated by a flexible, anchored, diaphragm, resilient means normally urging said diaphragm in a direction tending to contract one of said chambers, a plunger rod piercing said casing, the said one chamber and said diaphragm and fixedly connected to said diaphragm for movement therewith, said plunger rod having a portion engageable with the throttle valve, a bore in said plunger rod providing a first passageway interconnecting said chambers, restriction means associated with said bore to meter the air passing through said bore, an air inlet to said one chamber, a second passageway connecting said chambers including 1 a first by-pass portion connected between said one chamber and a push rod receiving bore, a second by-pass portion connected between the other chamber and the push rod receiving bore,

a valve in said push rod receiving bore intermediate the connections of the by-pass portions to the push rod receiving bore, a push rod slidably mounted in said push rod receiving bore, resilient means normally urging said push rod into engagement with said valve to open said valve, solenoid means energizable to disengage said push rod from said valve to close said valve, and an electrical circuit for said solenoid including vehicle speed responsive control means to automatically control energization of said solenoid.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,296,646 Matulaitis Sept. 22, 1942 2,314,570 Ball Mar. 23, 1943 

